When the comment you replied to mentioned "Chinese has gotten by for thousands of years without any plurals at all", I understood it to mean that Chinese has not featured any general system of marking plural by grammatical means[1], which is what is usually understood by the term "plural"[2], not that Chinese has no ability to express a more-than-one count distinction at all (which isn't the case in any language as far as I'm aware).

> It can't pluralize anything, but it can pluralize anything that refers to people and it is actively used in novel ways. I've seen someone refer to 美国的妈妈们; metonymy is not involved there.

It is productive in a limited sense in that way, but not as a general plural marker as you're arguing, and it's limited because 美国的妈妈们 means "American mothers" in that it necessarily refers to them as a collective group (which I argue is an instance of metonymy) rather than a set of more than one "American mother". For instance you cannot say *三个美国的妈妈们 to mean "three American mothers"; you must instead say 三个美国的妈妈 because 美国的妈妈们 can only ever refer to the entire collective group.

> I should note that this argument doesn't entirely hang together. You can make "the White House" explicitly plural in English by giving it a plural verb

This is a feature of UK English where collective nouns agree with plural forms of verbs. US English on the other hand, requires the singular form[3][4]. This has no bearing on how we analyze Chinese.

[1] https://en.wikipedia.org/wiki/Grammatical_number

[2] https://en.wikipedia.org/wiki/Plural

[3] https://victoryediting.com/collective-nouns/

[4] https://en.wikipedia.org/wiki/Collective_noun#Examples_of_me...